Constant GATE_USAGE_SYMBOL_RETRY 

pub const GATE_USAGE_SYMBOL_RETRY: &str = "usageSymbol.retry";

Gate section around the usage-symbol settle-wait in handle_references/ indexed_rename, held right after mir’s own per-file resolution first comes back empty (companion file not yet known) and before the wait-then-retry — lets a test force a companion declaring file to open while mir’s resolution attempt is still in flight, so the retry can observe mir resolving it correctly instead of falling through to the AST-heuristic FQN fallback.